The Food and Drug Administration said on Wednesday there was a shortage of Adderall, a treatment for attention deficit hyperactivity disorder, following intermittent manufacturing delays at Teva Pharmaceutical Industries Ltd.

Adderall is an FDA-approved prescription drug made of two stimulants amphetamine and dextroamphetamine.

Other manufacturers continue to produce amphetamine mixed salts, but there is not sufficient supply to continue to meet U.S. market demand through those producers, the U.S. health regulator said.

U.S.-listed shares of Israel-based Teva were down 2% at $7.90 in trading after the bell.

Teva did not immediately respond to a request for comment.